PTS Pali-English dictionary - The Pali Text Society's Pali-English dictionary
Vo°
Vo°,is commonly regarded as the prefix combnvi+ava° (i.e.vi+o°),but in many cases it simply represents ava° (=o°) with v as euphonic (“vorschlag”),as in vonata (=onata),voloketi,vokkanti,vokiṇṇa,voropeti,vosāpeti,vosāna,vossagga.In a few cases it corresponds to vi+ud°,as in vokkamati,vocchijjati,voyoga.(Page 651)